1. Field of the Invention
The present invention relates to a method and apparatus for measuring a use of radio resources in a wireless communication system. More particularly, the present invention relates to a method and apparatus for measuring a use of radio resources per traffic class.
2. Description of the Related Art
In the 3rd Generation Partnership Project (3GPP), which is responsible for standardizing the Universal Mobile Telecommunications System (UMTS), a Long Term Evolution (LTE) system is now under development as the next-generation mobile communication system for the UMTS system. LTE is a technology that realizes high-speed packet-based communications at a full data rate of about 100 Mbps, which is aimed to be commercialized in 2010. The Institute of Electrical and Electronics Engineers (IEEE) Technical Standard (TS) 36.314, which is a 3GPP Radio Access Network 2 (RAN2) standard, describes a method for measuring a Physical Resource Block (PRB) use among methods for measuring the use of radio resources in the LTE system. The use of PRBs, which is information used for inter-cell load balancing and Call Admission Control (CAC) in the LTE system, denotes the use of time and/or frequency resources. Thus, for the inter-cell load balancing, the PRB use should be accurately measured. Generally however, in the LTE system, a transport block includes a part other than the actual data, such as padding, and the PRB use measured by the conventional approach defined in TS 36.314 is calculated without considering the part other than the actual data, i.e., even the part other than the actual data in the transport block is proportionally calculated in the calculation process of PRB use, thus making it impossible to represent the exact load of the system.
In addition, the development of the LTE system up to now has not taken into consideration a multi-antenna technology for measurement of the PRB use. Therefore, if the multi-antenna technology is applied to the existing LTE system, different transport blocks may share the same PRB. In this case, a PRB use per traffic class (which is equivalent to Quality of service Class Identifier (QCI)) may be calculated as a value of 100% or more, even though its maximum value is defined as 100%.
In the LTE system, information about the PRB use may be exchanged between cells for load balancing. Assuming that for load balancing, the PRB use information is exchanged between cells and one cell supports a single antenna while another cell supports multiple antennas, PRB uses having the same value may actually indicate that the loads are at different levels. A description of such an occurrence will be given with reference to FIG. 1.
FIG. 1 illustrates the use of PRBs in transport blocks in a conventional multi-antenna system, in which a plurality of transport blocks sharing PRBs are transmitted via multiple antennas. For convenience, it is assumed that in the example of FIG. 1, one QCI belongs to each of transport blocks 101, 103 and 105, and the number of bits of padding and a MAC subheader is 0. In FIG. 1, since the transport block #0 101 uses PRB #0 and PRB #1 100%, its PRB use becomes 2, and in the same manner, a PRB use of the transport block #1 103 becomes 2, and a PRB use of the transport block #2 105 becomes 3. In the example of FIG. 1, since the total number of PRBs used is 4 (PRBs #0˜#3) and a sum of the number of PRBs used by the transport blocks #0˜#2 becomes 7, the total PRB use becomes 7/4*100=175%. Therefore, the conventional approach fails to accurately reflect the load of the multi-antenna system.
To address these and other drawbacks, a new approach is required that can better represent the actual load of the system considering the part other than the actual data in a transport block during measurement of radio resource use in the wireless communication system, and can accurately represent the load even when the multi-antenna technology is applied.